1. Field of the Invention
The present invention is directed to a hair clipper, and more particularly to an improved hair clipper capable of facilitating to cut hairs to any desired cut length without causing uneven hair cuts with a minimum manipulation force of adjusting the cut length.
2. Description of the Prior Art
A hair clipper with varying cut length capability has been described in U.K. Patent Application. No. 2 245 518A (U.S. patent application No. 712,097 now U.S. Pat. No. 5,325,589 in which a movable blade is moved relative to a stationary blade for varying a cut length of hairs by moving an adjuster handle mounted on a housing of the hair clipper in a direction along the longitudinal axis of the housing. The movable blade is interlocked with the adjuster handle through a linkage member in such a manner that the movable blade is moved in a rearward direction along the longitudinal axis to reduce the cut length when the adjuster handle is moved in a forward direction along the longitudinal axis. Therefore, the linkage member is useful for preventing unintentional excess cut of the hairs when the hair clipper is advanced toward the top of the head while gradually decreasing the cut length. However, since the movable blade is urged against the stationary blade by a torsion spring in order to give between the blades a suitable spring bias necessary for causing a hair shearing reciprocating motion of the movable blade on the stationary blade, a relatively large manipulation force is required to slide the adjuster handle and therefore the movable blade against a friction between the blades when adjusting the cut length of the hairs.
In addition, the adjuster handle has a latch means capable of stably holding a shearing position of the movable blade relative to the stationary blade during the shearing operation. The latch means includes a release knob projecting on a portion of the adjuster handle to be accessible by a finger of an operator manipulating the handle. The release knob is provided to unlatch the adjustor handle upon being pressed to thereby permit a sliding movement of the handle for varying the cut length. Eventually, the operator is required to press the release knob for sliding the adjuster handle besides the above described manipulation force. This is inconvenient and is therefore a cause of accumulating fatigue of a wrist or fingers of the operator when shearing the hairs while varying the cut length continuously and manually. Additionally, it may be expected that such linkage member and latch means create difficulties because of necessary complex structures.